Manually operated nailing machines heretofore have been limited to use with nails of one size, the size of the nail being determined by the length of the double shanks of the nails which can vary from one inch to an inch and a quarter to an inch and a half. The inability to use the machines with nails of different sizes, of course, places restrictions on the type of work which can be performed by the machine. Thus, for example, a machine limited to use with one and a quarter inch nails for securing roofing shingles in place could not be used with one inch nails for use in laying down plywood flooring. A different machine would be needed. Yet another shortcoming of prior nailing machines of the type here under consideration centers on alignment of the nail to be driven into a workpiece and the workpiece itself. It is important that each nail, as it is severed by the driving blade of the machine, be aligned at substantially a right angle with the workpiece, otherwise the nail will not be completely embedded in the workpiece, or will be bent under the force of the driving blade, requiring another nail, and another blow from the resilient headed maul or mallet wielded by the operator. Conventional nailing machines rely upon the feed mechanism, namely, the pusher for the nailing strip, to position, and hold, the nails in alignment with the driving blade and the workpiece. In practice, such an arrangement is unsatisfactory, and does not meet the problem.